I wish we can have a feature that allows to start the calendar UI from Monday instead of Sunday.
Or even exclude any of the days of the week
Hi there, @Caroline_Lopes and welcome to the Community 
The first day of the week in the calendar depends on the language selected in the settings.
Currently, you’re using the Portuguese (Brazil). The first day of the week in Brazil is Sunday, which is why Sunday appears first in your calendar:
However, if you switch it to Portuguese (Portugal), the 1st day of the week will be Monday:
Please let me know if this clears things up or if you have any questions left 